The combination of cocaine abuse and HIV infection represents a unique challenge to both researchers and health professionals. Both HIV and cocaine abuse can cause accelerated atherosclerosis and cardiovascular complications possibly resulting from separate mechanisms. These etiologies have not been thoroughly investigated. While regimens containing protease inhibitors (PI) improves survival in patients with HIV, their impact on atherosclerosis still is not fully understood. With longer survival, increasing numbers of HIV infected individuals who also abuse cocaine may face serious threat from cardiovascular complications. The overall goals of this study are (1) to describe prospectively the etiology and natural history of atherosclerosis and the ability of non-invasive tools to measure atherosclerotic burden in black men and women with HIV infection who abuse cocaine, and (2) to investigate whether HIV infection, cocaine abuse and protease inhibitor treatment accelerate atherosclerosis. The proposed study will enroll 160 black men and women with HIV infection and without cardiovascular diseases (40 cocaine (+) and PI(+), 40 cocaine(+) and PI(-), 40 cocaine(-) and PI(+), and 40 cocaine (-) and PI(-)) and 80 black men and women without HIV infection and cardiovascular diseases (40 cocaine (+) and 40 cocaine (-)), and perform baseline interview, clinical examinations, ECG, echocardiographic examinations, lipid profiles and spiral CT for coronary calcium. These study subjects will be re-examined two years later and followed up for at least two years. This study has the potential to provide critical information about the impact of HIV, cocaine abuse and PI on the development of atherosclerosis.